The tax man could come calling on any top cricketers who pocketed cash for fixing matches overseas, but have not declared it back in New Zealand.

That could amount to tax dodging or "evasion", with stiff penalties amounting to 150 per cent of the tax owed and matters could be worse if they were caught trying to hide the payments.

Tax experts say jail time was not impossible for tax evasion on something like cash for match-fixing, though unlikely.

But there have been cases where people had been jailed for pocketing PAYE and GST payments. At worst, if people knowingly evaded tax, they could be fined up to $50,000 and/or face up to five years in jail.

But moving any match-fixing cash into another country and putting it into something like diamonds or property could make it hard to argue it was not tax evasion, a tax expert said.

It was understood most New Zealand cricketers would live in New Zealand for tax purposes, so they should declare any income, illegal or not.

In a report in the Dail Mail in Britain, Black Caps captain Brendon McCullum's testimony to the ICC anti-corruption unit included a statement that he had been told by "player X" that match-fixing cash should not be sent back to New Zealand.

"He explained that he had a man in Dubai who was associated with cricket. Through him you purchase a property in Dubai which you retain for a couple of years before selling it.

"The money could then be moved wherever you want to send it because to all intents and purposes, it would appear to be profit from property deals rather than fixing. X told me the name of that man in Dubai."

Chris Cairns has outed himself as "player X" but vehemently denies the accusations.

An Inland Revenue spokesperson confirmed that New Zealand tax residents were required to pay tax on their worldwide income, "including income from illegal activities".

If Inland Revenue received information regarding cash payments to a New Zealand resident "we would look into that information," an Inland Revenue spokesperson said yesterday.

In the past, Inland Revenue said it had recovered tax from New Zealanders for overseas payments and bank accounts that has "amounted to evasion".

"We often utilise information and intelligence which is available through various means to do this," Inland Revenue said, including share information and bank account details with some foreign tax authorities, though it would not comment on any individual cases.

Deloitte chief executive Thomas Pippos said tax was payable on illegal income, and if people knowingly evaded tax, there could be criminal penalties, including prison. "It is very serious."

And if people moved money from one country to another, say putting it into diamonds or property in the Middle East to conceal the money, that would not change the tax owed. Trying to hide the money in another country would just make it harder to argue that it was anything other than tax evasion.

Another source said governments were cracking down on tax evasion through offshore bank accounts.

"The revenue authorities are getting more joined up," the source said "So it is harder to duck outside the revenue net . . . but it is not impossible".

There were claims of cash payments made to rugby players touring South Africa many years ago, but it was hard to know if they were correct, where the cash ended up or if tax was paid, the Wellington source said.